First of all, key signature tells you the tonality. Look for the sharps and flats which then correspond to a certain scale e.g. C major/A minor has no sharps and flats. Next look at the time signature to work out the metre. C is common time which is 4/4. Then you go into the details with the notes (pitch, duration). There are also dynamic markings (e.g. f = forte = loud and also accents, staccato etc). There are different types of clefs (treble, alto, bass, percussion) so be sure you are reading in the respective clef. E.g. middle line of treble stave is a B note. Um... There's heaps more but yeah, there's a start.
IMPORTANT: You are doing the course music 1 so scores are not essential (can get through without knowing them too well). But for Composition a reasonable understanding is required as you have to hand up scores with your notated music on them.